1
Study of environmental and human health impacts of
firefighting agents
A technical reportAnna Kärrman, Filip Bjurlid, Jessika Hagberg, Niklas Ricklund, Maria Larsson, Jordan Stubleski, Henner Hollert
2 Report written by Anna Kärrman, Filip Bjurlid, Jessika Hagberg, Niklas Ricklund, Maria Larsson, Jordan Stubleski at MTM Research Centre, and Henner Hollert at Aachen University, Germany.
Published and available in DiVA (www.diva-portal.org).
MTM Research Centre
School of Science and Technology Örebro University, Sweden anna.karrman@oru.se
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CONTENT
Summary... 4
Sammanfattning ... 6
Abbreviations of highly fluorinated substances ... 8
1. Background ... 9
2. Analysis of firefighting agents on the Swedish market ... 10
2.1 Selection of fire agents ... 10
2.2 Chemical analysis ... 11
2.3 Ecotoxicological analysis ... 13
2.4 Conclusion ... 23
3. Formation of by-products during extinguishing using different techniques ... 24
3.1 Method and execution ... 24
3.2 Chemical analysis ... 26
3.3 ResultS ... 28
3.4 Conclusion ... 34
4. Pilot study on highly fluorinated substances in firefighter´s blood ... 34
4.1 Method ... 35
4.2 Results ... 35
Acknowledgment ... 39
Literature ... 40
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Summary
A study was performed by Örebro University on behalf of the Swedish Civil Contingencies Agency, where extinguishing agents are studied from an environmental and health perspective. The purpose of the study is to gain more knowledge about the chemicals firefighters and the environment are exposed to from the use of firefighting agents, and if alternative methods results in less harmful by-products. The study can be divided into the following parts: 1) chemical and ecotoxicological analysis of selected firefighting agents, 2) study the formation of hazardous chemicals when extinguishing fires using different techniques, 3) conduct an initial survey of Swedish fire fighters occupational exposure of highly fluorinated substances. This report describes the work carried out from 2014 to 2015.
Firefighting agents that were included in the study were several class A foam for fires in fibrous materials, class B foams for liquid fires, and the additive X-fog. Class A and B foams on the Swedish market contains surfactants with the characteristic hydrophobic and hydrophilic properties. All class B foams included in the study contained fluorinated surfactants. The predicted long-term effect of the identified fluorinated surfactants is that they will undergo environmental transformation in more than one step until a carboxylic acid state with a fully
fluorinated carbon chain is obtained. From there no further transformation or degradation is expected. These acids are as persistent in the environment as PFOS, which is banned in EU. They are however more water soluble than PFOS meaning that elimination time in organisms including humans are reduced, uptake in water rich crops like vegetables are increased, and removal from drinking water is more difficult.
All products tested showed clear effects in all conducted ecotoxicological tests. The strongest toxic effects were found for the primary consumer Daphnia magna which are affected by firefighting agents at lowest
concentration. Differences in toxic responses between the tested agents were observed, X-fog showed the lowest toxic response based on the concentrated product for all tests. The marine bacteria Vibrio fischeri actually started to grow with lower concentrations of X-fog and a high concentration of 21 vol% concentrated product was needed to obtain the effect concentration indicating an eutrophication effect. This is probably due to the X-fog´s composition of salts like ammonium and sodium which functions as nutrition. There were minor differences between the foam products with exception for One Seven A that gave the highest toxic response (e.g. lowest effect concentration). It should be noted that acute toxic effects are seen for class A foams as well as for class B foams and there are little differences in aquatic toxicity between these foam classes.
Formation of hazardous by-products during fire extinction was studied by fire tests in containers using spray nozzle, cutting extinguisher, CAFS, and cutting extinguisher with additive X-fog. A general trend in the results is that cutting extinguisher with additive X-fog generated the lowest concentrations of by-products. It was also using cutting extinguisher with additive X-fog that least volume of water was used, least number of re-ignitions occurred, and no fire water could be collected from the containers on the floor. The cutting extinguisher together with X-fog resulted in the fastest extinction process and most likely resulted in least hazardous compounds in the flue gas and soot.
Highly fluorinated substances both have and are still used in Class B firefighting foams. These substances have a long residence time in the body, why it is possible to see an occupational exposure, even many years after it ceased. To study firefighter´s exposure for firefighting agents a pilot study was conducted in Helsingborg. The concentrations of highly fluorinated substances are low in firefighters from Helsingborg and there are no clear
5 association between serum levels and years worked as a firefighter. In contrast, 10 % of the firefighters had about 2-3 times higher PFOS concentrations and / or 5-20 times higher PFHxS levels compared to the average concentrations in other studies from Sweden and the USA. This may be a sign of an occupational exposure but too few individuals are included in the study achieve statistical certainty. The reason for the general low
concentrations in firefighter´s could be that the exposure for firefighting agents are low and that precautions are taken when handling firefighting products. Another explanation could be that handling and usage of foams for class B fires have been rare. The historical usage of class B foams at the Helsingborg stations could not be properly elucidated.
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Sammanfattning
På uppdrag av Myndigheten för Samhällsskydd och Beredskap har en studie utförts av Örebro universitet där brandsläckningsmedel studeras ur ett miljö- och hälsoperspektiv. Syftet med studien är att öka kunskapen om vilka kemikalier brandmän och miljön utsätts för vid användning av släckmedel samt om olika släckmetoder orsakar olika mycket skadliga kemikalier under släckning. Den här rapporten beskriver arbete som utförts 2014-2015.
Syftet med studien är att få mer kunskap om vilka kemikalier brandmän och miljön utsätts för vid användning av släckmedel samt om alternativa släckmetoder orsakar mindre skadliga kemikalier. Studien kan delas upp i följande delar; 1) kemiska och ekotoxikologiska analyser av utvalda släckvätskor, 2) studera bildandet av farliga kemikalier vid släckning av brand med olika tekniker, 3) genomföra en inledande undersökning om svenska brandmäns yrkesexponering av högfluorerade kemikalier.
Släckmedel som ingick i studien var ett antal klass A skum för fibrösa bränder, klass B skum för vätskebränder, samt tillsatsmedlet X-fog. A och B- skum på den svenska marknaden innehåller tensider med karakteristiska hydrofoba och hydrofila egenskaper. Alla klass B skum som ingår i studien innehöll fluorerade tensider. Den långsiktiga effekten av de identifierade fluorerade tensiderna förutspås vara en omvandling tills en karboxylsyra med en helt fluorerade kolkedja erhålls. Därifrån sker ingen ytterligare omvandling eller nedbrytning. Dessa syror är extremt svårnedbrytbara i miljön på samma sätt som perfluoroktansulfonsyra (PFOS), som idag är förbjuden. De är dock mer vattenlösliga än PFOS vilket innebär att elimineringstiden i organismer inklusive människor är kortare, upptag i vattenrika grödor, t.ex. grönsaker ökar, och de är svårare att rena från vatten. Alla testade släckprodukter visade tydliga effekter i alla genomförda ekotoxikologiska tester. Den starkaste toxiska effekten konstaterades för den primära konsumenten Daphnia magna som påverkas av släckmedel vid lägst koncentration. Skillnader i giftighet mellan de testade släckmedlen kunde också konstateras, X-fog visade den lägsta toxiska effekten i alla test baserat på den koncentrerade produkten. Den marina bakterien Vibrio fischeri började faktiskt växa vid låga koncentrationer av X-fog och hela 21 vol% koncentrerad produkt krävdes för att uppnå effektkoncentrationen vilket indikerar att X-fog kan ge en övergödande effekt. Detta beror sannolikt på X-fog's innehåll av salter såsom ammonium och natrium fungerar som näring. Det fanns endast mindre skillnader mellan skumprodukterna med undantag för One Seven A som resulterade i den högsta toxiska respons (d.v.s. lägsta effektkoncentration). Det bör noteras att det inte finns skillnader i toxicitet mellan klass A skum och klass skum B.
Bildandet av miljö- och hälsofarliga biprodukter studerades genom brandtest i containrar med strålrör,
skärsläckare, CAFS, och skärsläckare med tillsatsmedlet X-fog. En allmän trend i resultaten är att skärsläckare och X-fog genererade lägst koncentration av biprodukter såsom bromerade dioxiner, VOC, och PAHer i sot och rökgas. Det var också med skärsläckare och X-fog som minst volym vatten användes, minst antal återtändningar inträffade, och inget släckvatten kunde samlas från behållare på golvet. Skärsläckaren tillsammans med X-fog hade det snabbaste släckförloppet vilket troligen är orsaken till att minst farliga föreningar detekterades i rökgas och sot.
Högfluorerade ämnen både har och används fortfarande i klass B släckskum. Ämnena har en lång uppehållstid i kroppen varvid det går att se en yrkesexponering även många år efter den upphört. För att studera exponering av släckmedel för brandmän utfördes en undersökning av brandmän i Helsingborg. Halterna av högfluorerade
7 ämnen konstaterades låga i brandmän från Helsingborg och det finns inte någon säkerställd koppling mellan serumnivåer och antal yrkesverksamma år som brandman. Däremot hade 10% av brandmännen ca 2-3 gånger högre PFOS-halter och /eller 5-20 gånger högre halter perfluorhexansulfonsyra (PFHxS) jämfört med
medelvärdet i andra studier från Sverige och USA. Detta kan vara ett tecken på en yrkesexponering men för få individer ingår i studien för att kunna säga med säkerhet. Anledningen till de låga serumhalterna kan vara att exponeringen för släckmedel är låga och att försiktighetsåtgärder vidtas vid hantering av produkter. En annan förklaring kan vara att hantering och användning av skum för klass B bränder har varit sällsynta. Den historiska användningen av klass B skum vid Helsingborg stationerna kunde inte verifieras i den här studien.
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Abbreviations of highly fluorinated substances
Per- and polyfluorinated alkyl substances PFAS
Perfluorobutanoic acid PFBA
Perfluoropentanoic acid PFPeA
Perfluorohexanoic acid PFHxA
Perfluoroheptanoic acid PFHpA
Perfluorooctanoic acid PFOA
Perfluorononanoic acid PFNA
Perfluorodecanoic acid PFDA
Perfluoroundecanoic acid PFUnDA
Perfluorododecanoic acid PFDoDA
Perfluorotridecanoic acid PFTrDA
Perfluorotetradecanoic acid PFTDA
Perfluorobutane sulfonic acid PFBuS
Perfluorohexane sulfonic acid PFHxS
Perfluorooctane sulfonic acid PFOS
Perfluorodecane sulfonic acid PFDS
6:2 Fluorotelomer Sulfonate 6:2 FTS
Perfluorooctane sulfonamide PFOSA
N-Methylheptadecafluorooctane sulfonamide N-MeFOSA N-Ethylheptadecafluorooctane sulfonamide N-EtFOSA N-Methylheptadecafluorooctane sulfonamidoethanol N-MeFOSE N-Ethylheptadecafluorooctane sulfonamidoethanol N-EtFOSE
Fluorotelomer alcohol FTOH
1H,1H,2H,2H-perfluoro-1-octanol 6:2 FTOH 1H,1H,2H,2H-perfluoro-1-decanol 8:2 FTOH 1H,1H,2H,2H-perfluoro-1-dodecanol 10:2 FTOH Fluorotelomer unsaturated carboxylic acid FTUCA
Fluorotelomer carboxylic acid FTCA
Fluorotelomermercaptoalkylamido sulfonate 6:2 FTSAS
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1. Background
Misuse of firefighting agents, both in real fire situations and exercises, results in a large impact on the environment and can have devastating effects on sensitive aquatic environments as well as private and municipal water supplies. An estimate made by the Swedish drinking water producers and the Swedish Water and Waste Water Association shows that 22% of the drinking water in the country is affected by fluorinated surfactants (Holmström et al 2014) which, partly originates from fire exercise areas. Converted into the number of drinking water customer’s results in every fourth Swede that has a tap water impacted by fluorinated surfactants. The most known water pollution cases include Tullinge, Kallinge and Uppsala. Moreover, there is a large, yet unknown number of contaminated sites in Sweden that must be remediated. The social costs in the current, known situation cannot be estimated. Fluorinated surfactants are primarily used in firefighting agents designed for liquid fires (KEMI 2015) but it is not only the fluorine-containing foams that are potentially harmful to the environment and health. Foams and other extinguishing agents are acutely harmful and extinguishing foams have been shown to significantly elevate the levels of organic pollutants, such as dioxins, in the
extinguishing water (SP 2005). Firefighting agents can more or less help to leach out and transport the toxic fire remains at risk of irreversible damage to the environment. Number of interventions per year where potential emissions can damage groundwater or environmentally sensitive areas are estimated at 10,500, of whom 3500 are car fires and 7000 are fires in buildings (MSB 2016). Add to that exercises performed by emergency services and authorities, and more rare fires such as petroleum fires and industrial fires
Hazardous substances can be formed during fire of different materials as well as in the flue gas when the fire is depleted. Depending on the extinguishing method used, different thermal conditions are created in the fire room. Different firefighting agents and techniques extinguish fires in different ways. Some lower the
temperature of the flue gas, while others lower the temperature of the burning material. The firefighting agent´s efficiency in lowering the temperature is crucial for reducing the formation of hazardous by-products and it should be examined whether various firefighting methods can contribute to or reduce the formation of toxic substances. If such differences exists it can cause negative effects on firefighter’s health and the environment. There is a high demand from municipalities (emergency services) and government agencies (the Swedish Civil Contingencies Agency, Swedish Armed Forces, and the Swedish Chemicals Agency) for more knowledge on environmentally friendly methods. The knowledge of what firefighting agents are made of and what
environmental impact they have is low. This has contributed to a situation in where operations and exercises differs between different emergency services. As a result of the relatively low concentrations of chemical additives in the extinguishing products, market products are not subject to any legal testing or reporting requirements. Therefore a development of knowledge is needed to make firefighting efforts nationally eco-efficient and sustainable.
The present study aims at providing more knowledge on firefighting agents environmental and health impact and can be divided into three parts:
1) Chemical and ecotoxicological evaluation of selected fire extinguishing agents to increase knowledge on what kind of chemicals are being used and released, and what the environmental effects are. 2) Study the formation of hazardous chemicals during extinguishing of fires using different techniques; are there firefighting agents and/or techniques that results in less by-products?
10 3) Conduct an initial survey of Swedish fire fighters occupational exposure of highly fluorinated
chemicals that are or have been present in firefighting agents
2. Analysis of firefighting agents on the Swedish market
At the request of the Swedish Contingencies Agency and the Swedish Chemical Agency, Örebro University performed several different analysis of selected firefighting agents present on the Swedish market in 2014. The aim was to increase the knowledge of the toxicity of firefighting agents and to identify the main ingredients in order to evaluate the long term toxicity to the environment and humans. A special focus were to identify the presence of per- and polyfluorinated alkyl substances (PFAS) including precursor compounds.Producers consider the ingredients in their products as trade secrets thus firefighting agents can contain a variety of additives and the present ingredients needs to be elucidated due to environmental and health concerns. Fires in fibrous materials, e.g. building fires also called class A-fires, are today extinguished with fluorine-free foam, water or water mist, with or without additives. Fires in e.g. flammable liquids also called class B-fires are extinguished with foam that often contains highly fluorinated substances. Surfactants, or detergents, used in foams affects the surface tension of water which facilitates formation of a film. Addition of fluorine to the surfactant makes it more stable and heat resistant. The surface properties are also increases, i.e. a more efficient lowering of the water´s surface tension.
There are many different techniques and extinguishing agents to choose from but an overall risk- and efficiency assessment is missing and there are no national recommendations.
Restrictions of foam containing highly fluorinated substances, albeit with significant exceptions, are proposed by the Swedish Chemical Agency however fluorine-free fire extinguishing agents are being introduced on the market without adequate environmental assessment. A complete register of the products is also lacking. A survey of the manufacturers and suppliers of firefighting foams on the Swedish market was conducted in 2014 on behalf of the Swedish Chemical Agency (KEMI 2014).
A selection of firefighting agents were studied with respect to i) chemical analysis in order to identify the main ingredients and presence of highly fluorinated substances, ii) ecotoxicological analysis to assess environmental effects.
2.1 SELECTION OF FIRE AGENTS
The firefighting agents included in the present study was selected based on the above mentioned survey report and available public registers on imported and used volumes from 2012 (KEMI 2014). One additive for water mist extinguishing was also included in the study. The agents included were:
A-class foams for fires in fibrous materials (name(distributor)):
Forest (Dafo), OneSeven A (NFRS), Unifoam Bioyellow (Kempartner) B-class foams for fires in flammable liquids:
Sthamex AFFF 3% (Dr Sthamer/Presto), Alcoseal 3-6% (Angus/Kidde), AFFF 3% (Dafo), Towalex AFFF (Tyco), OneSeven B-AR (NFRS), ARC Miljö (Dafo)
Additive for water mist: X-fog (X-fire AB)
11 Selected products were kindly donated from distributors and users. Firefighting products were provided from the different sources and were sampled by the provider, between 200 mL – 5000 mL, in clean plastic containers (not containing Teflon or other fluoropolymers) during fall 2014.
2.2 CHEMICAL ANALYSIS
The firefighting products were sub-sampled and diluted (between 100 to 10000 times) with laboratory produced water (MilliQ-quality) and methanol (LC-MS grade) and was filtered (GHP filters, 0.2 µm) before analysis.
Detailed information on the analytical procedure are described elsewhere (KEMI 2015).
Chemical analysis with the aim to identify main ingredients in firefighting agents was performed using non-target screening using liquid chromatography coupled to mass spectrometry (Acquity UPLC Xevo Synapt qToF (Waters Corporation, Milford, USA) with atmospheric electrospray). This technique is suitable for identifying unknown substances that are highly to moderately water soluble substances and that relatively easily can be transformed into an ionized state. A diluted solution (10000 times) of the products was analyzed. Non-target screening was done in both positive and negative mode and by the MSE-technology that maximize the
information obtained from a single analysis by switching low collision energy mode, to obtain precursor ion data, with a high collision energy ramp to obtain fragment ion data. Tentatively identification of unknown compounds was performed using softwares from Waters Corporation (MassLynx, MarkerLynx, UNIFI) elemental composition and by matching structures with the database Chemspider.
Target analysis of highly fluorinated substances was also performed using liquid chromatography and gas chromatography coupled to mass spectrometry. Approximately 30 highly fluorinated substances for which authentic standards are available were analyzed in firefighting agents using different instrumentations (Acquity UPLC Xevo TQ-S MS/MS (Waters Corporation, Milford, USA) and 7890A GC system with a 5975C MSD (Agilent Technologies, Palo Alto, CA). Quantification of target compounds was performed by adding labeled internal standards to the diluted (approximately 10 mg to 1 mL) products. Interferences in the analysis from sample matrix were corrected for by the labeled standards. Labeled internal standards were added to clean methanol/water and were analyzed as a blank control. Several blank injections were performed to monitor possible system carry-over or memory effects.
2.2.1 Results Non-target analysis
Foams are complex mixtures of additives such as surfactants and a mixture of chemicals are present in the products. The process of identifying ingredients is therefore a tedious and difficult task. Both class A and B foams resulted in complex mixtures of signals. Tentative identification was made when the structure could be
confirmed by the presence of the molecular ion and at least two product ions. Moreover, any organic component that for some reason does not ionize under the used analytical conditions (positive and negative atmospheric electrospray ionization together with water/methanol/ammonium acetate or formic acid) cannot be detected. The signal intensity may not be representative of the actual concentration and the homogeneity of the foam samples have not been studied which may be a source of uncertainty both in the non-target and target analysis. For unequivocal identification of unknowns reference standards are required. Examples of structures found in different firefighting foams can be seen in table 1. Special focus was on identification of unknown highly fluorinated substances. All class B foams and none of the class A foams contained highly fluorinated substances.
12 The found structures containing organofluorine were compared to literature and could be confirmed to be present in firefighting foams included in other studies (D´Agostino and Mabury 2014; Moe et al. 2012; Weiner et al. 2013) (1-4) for all cases except for ARC Miljö.
A list of abbreviations of fluorinated substances mentioned here is found on page 6.
Fluorotelomermercaptoalkylamido sulfonate with six fluorinated carbons (6:2 FTSAS) was identified in Towalex master, Alcoseal 3-6%, and Skum AFFF3%. Fluorotelomer sulfonamide alkylbetaine (6:2 FTAB) was identified in Sthamex, Alcoseal 3-6% and Towalex Master 3%. ARC Miljö also contains the 6:2 fluorotelomer chemistry which could be identified as 6:2 fluorotelomer sulfonamide amine however one of the main signals represented a structure in where the amine group connected to the sulfonyl group bears one oxygen. 6:2 FTSAS has previously been reported to be present in AFFFs with product names F-500, Tridol S3%, Anslite 3% AFFF-DC-3, Niagara 1-3, and Ansul Ansulite ARC (Weiner et al. 2013). 6:2 FTAB has been reported to be present in Forafac 1157, F-500, Niagara 1-3, and Tridol S (D´Agostino and Mabury 2014; Moe et al. 2012).
Table 1. Ingredients tentatively identified in different firefighting foam products by qToF analysis
Examples of surfactants in class A foams Examples of surfatcatnts in class B foams
Nonyl hydrogen sulfate 6:2 FTAB fluorotelomer sulfonamide alkylbetaine
Octyl hexylcarbamate 6:2 FTSAS fluorotelomermercapto-alkylamido sulfonate
N-tetradecylacrylamide 6:2 fluorotelomer sulfonamide amine
Presence and levels of known fluorinated substances
Highly fluorinated substances were detected in all class B foams and none of the class A foams. Known PFAS was found in all products analyzed, most commonly detected were short chain perfluorinated carboxylates, from low ppb levels up to ppm levels. Perfluorohexanoic acid (PFHxA, C6) was found in highest concentrations, up to 14 000 µg/kg. Fluorotelomer sulfonic acid with six fluorinated carbons (6:2 FTS) was quantified in all studied products up to 10 000 µg/kg. Bioaccumulating perfluorinated acids (C ≥ 7) and perfluorinated sulfonic acids were detected less frequent and in lower concentrations. Perfluorooctane sulfonic acid (PFOS) was found in two different products from users, but not in the corresponding samples from sealed containers or distributors indicating probable site contamination from previous firefighting products. The presence of PFHxA and 6:2 FTS can be residues from the manufacturing process or due to storage degradation. The connection between the PFAS-profile (target analysis) and the identified structures is clear, traces of C6 carboxylic acid and 6:2
13 fluorotelomer sulfonate in the mg/kg range are present in products that has the 6:2 telomer configuration as part of one of the major organic molecules.
Other PFAS-profiles in samples collected from users can be due to contamination from previously used products. There is also a possibility that users keep older products that has the same name as current products but in where the ingredients have been replaced over time.
More information regarding class B firefighting foams are available elsewhere (KEMI 2015).
The six selected products for non-target analysis all contained fluorinated telomer products with 6:2
configuration including mercaptoalkylamido sulfonate, sulfonamide amine, and sulfonamide alkylbetaine. The connection between the PFAS-profile (target analysis) and the identified structures is clear, residues of C6 and shorter carboxylic acids and C6 fluorotelomer sulfonate in the mg/range are present in products that has the 6:2 telomer configuration as part of the precursor molecule. Other PFAS-profiles in products obtained from users can be due to contamination from previously used products and/or equipment. The results from this limited study indicates that contamination from previously used products might be widespread.
Water mist additive X-fog
Using previously described methodology did not result in any information regarding the additive X-fog. The conclusion from the analysis is that X-fog does not contain organic structures that are ionized under electrospray conditions. This does not however rule out presence of organic structures but the content of X-fog is much different compared to the foam products. Further analysis on a more elementary basis was therefore made; analysis using ICP-MS showed high concentrations of sodium and calcium and ion chromatography showed high levels of for example chloride, acetate, and ammonium.
2.3 ECOTOXICOLOGICAL ANALYSIS
Environmental effects can occur both acute and/or on a more long term basis. Acute effects occurs immediately in the discharge area for a short time after the emission and usually close to the source. Chemical´s causing only acute effects may lead to additional impacts if they reach the groundwater. Long term effects on the other hand can occur during some time after the release. Long-term effects can be related to a chemical´s persistence, e.g. slow or non-existing degradation in the environment and/or metabolization in organisms. Accumulation in organisms, e.g. higher concentration in the organism compared to its surrounding, is also an example of long term effects. Distribution to other areas, sometimes far from the contamination source can be a consequence of a chemical´s persistence.
Different negative effects can occur in different environmental compartments. For example release of chemicals into air gives a different effect scenario compared to chemicals released into a water stream or soil. The
measured environmental effect is depending on the chemical and physical properties of the chemical,
concentration of the chemical, time of exposure, and type of organisms that comes in contact with the chemical. In the present study a selection of firefighting agents were evaluated based on acute effects in the aquatic environment. The selection of organisms from the aquatic environment were made based on the fact that firefighting agents are water soluble and there is a risk that emissions will reach the aquatic environment. Aquatic organisms are also among the most sensitive organisms and are therefore suitable for evaluation of environmental effects. The test systems included in the present study are algae (Desmodesmus subspicatus), fish
14 embryo (Danio rerio), freshwater water flea Daphnia magna and the marine bacteria Vibrio fisheri. An overview of the tested products and results obtained in the different tests expressed as EC50 values in volume% is given
below.
X-Fog One Seven A ARC Miljö Sthamex AFFF Towalex Master
Recommended use
A class A class B class (incl. alcohols) B class B class Algae growth (72h) 0.442% 0.010% 0.168% 0.036% 0.260% Fish embryo survival (48h) 0.409% 0.001% 0.339% 0.037% 0.088% Dapnia -survival (48h) 0.057% 0.006% 0.152% 0.096% 0.169% Marine bacteria Vibrio fisheri (15min) 21% 0.030% 0.016% 0.085% 0.095%
2.3.1 Algae growth inhibition test
To assess effects towards primary producers, ARC Miljö, One Seven, Sthamex and Towalex were investigated in the algae growth inhibition test using unicellular green algae Desmodesmus subspicatus. These freshwater algae belong to the phylum Chlorophyta. Primary producers like green algae are important food sources for many other aquatic organisms, thus they have a fundamental position in aquatic food webs.
In the algae test the inhibition of growth of unicellular algae strains is used to quantify the effects of chemicals in aqueous solutions. For this purpose the growth rates of exposed algae populations are compared to those of unexposed negative controls. Due to short generation cycles of the used test organism there are multiple generations of algae cells produced throughout the test duration (72 hours). Hence the algae growth inhibition test can be denoted as a chronic assay.
The algae growth inhibition test was conducted according to OECD Guideline 201 (2011) using OECD medium. The test organism Desmodesmus subspicatus CHODAT (SAG 86.81) originated from the Culture Collection of Algae at Göttingen University, Germany (SAG). The strain is cultivated at the Institute for Environmental Research (RWTH Aachen University).
15 Table 2. Concentrations (in volume %) prepared for the algae growth inhibition tests using Desmodesmus subspicatus.
ARC Miljö Tests 1, 2, 3 0.031 0.063 0.125 0.25 0.5
One Seven A Test 1 0.0001 0.0005 0.001 0.005 0.01 Tests 2.3 0.001 0.005 0.01 0.05 0.1 Sthamex Tests 1.3 0.005 0.01 0.05 0.1 0.5 Test 2 0.0005 0.001 0.005 0.01 0.05 Towalex Tests 1.2.3 0.01 0.05 0.1 0.5 1 X-fog Tests 1. 0.031 0.063 0.125 0.250 0.500 Tests 1.2.3 0.125 0.250 0.500 0.750 1.000
The tests were conducted in 24 well plates (TPP AG. Trasadingen. Swiss). For each test concentrations and negative control were inoculated with about 5x103 cells/mL and tested in three replicates (wells) containing 2
mL. The well plates were incubated at 23±2 C under suitable light conditions and continuous shaking. Chlorophyll fluorescence was measured at the beginning of the test and after 24, 48 and 72 hours using an Infinite M200 microplate reader (Tecan Group Ltd.. Männedorf. Swiss). The statistical evaluation was conducted using the software ToxRat (ToxRat Solutions GmbH. Alsdorf. Germany). The software performed probit analysis using maximum-likelihood regression to compute concentration-response curves and EC50(72h) values.
Results
Each substance was investigated in three independent algae growth inhibition tests (named as Test 1, 2, and 3). Examples of the concentration-response curves of the tests are shown in Figure 1 and the complete curves are shown in Figures A1-A5 in the appendices. The corresponding EC50(72h)-values calculated mean values and
standard deviations are summarized in Table 3.
Table 3: EC50(72h)-values (mean values and standard deviations (SD)) determined from three independent algae growth inhibition tests using Desmodesmus subspicatus.
EC50(72h) [vol%] mean ± SD ARC Miljö 0.168 ± 0.031 One Seven A 0.010 ± 0.004 Sthamex 0.036 ± 0.023 Towalex 0.260 ± 0.218 X-fog 0.442 ± 0.238
In the algae growth inhibition test the lowest mean EC50(72h) indicating the highest toxic potential for primary
producers was found for One Seven A (0.010±0.004 vol%). The mean EC50(72h) of Sthamex (0.036±0.023 vol%)
and ARC Miljö (0.168±0.031 vol%) were higher. Towalex showed the highest variability between the three conducted tests (0.083 vol%, 0.193 vol%, and 0.504 vol%). With 0.442±0.238 vol% the highest mean EC50(72h)
16 all three conducted tests. The maximum averaged growth inhibition for this concentration was observed in Test 3 with a mean value of 82.8 % inhibition (Appendix Table A1).
All conducted tests complied with the validity criteria stated in OECD 201 (2011). The pH-values were monitored according to OECD 201. Major pH-shifts of more than 1.5 units were measured for Sthamex at 0.5 vol% and for One Seven at 0.1 vol% and 0.05 vol%, the other tests showed no abnormalities.
A B
C D
E
Fig. 1: Examples of concentration-response curves in the algae growth inhibition assay for A: ARC Miljö, B: OneSeven A, C: Sthamex, D:Towalex, E: X-fog after 72 hours. The dots represent the single replicate values. The solid line shows the fitted concentration-response curve while the dashed lines illustrate the 95 %-confidence limits.
17
2.3.2 Fish Embryo Acute Toxicity Test with Danio rerio
The acute toxicity test on fish (OECD 203) is today an internationally acknowledged and standardized method within chemical risk assessment. During the last years chemical testing on fish and other vertebrates has raised ethical concerns as the animals may experience pain and distress (Braunbeck et al. 2005) which is not in line with current animal welfare legislation. Focusing on ethical considerations. Russell and Burch (1959) were the first to suggest that proper experimental design should include methods that refine techniques to lessen pain or distress of animals, reduce the number of animals necessary for a particular test, or replace animals with non‐ animal models. This concept became known as the ‘Three Rs’ of alternative methods: refinement, reduction, and replacement and is now embedded in national and international legislation regulating the use of animals in scientific procedures. Animal alternative considerations have also been incorporated into new European REACH regulations through strong advocacy for the reduction of testing with live animals. One of the most promising alternative approaches to classical acute fish toxicity testing with live fish is the Fish Embryo Acute Toxicity (FET) test. The FET test has been standardized at the international level as DIN EN ISO 15088 and OECD guideline 236 for the determination of the acute toxicity of waste water and chemicals, respectively.
The test organism used in the OECD guideline is the zebrafish (Danio rerio), a tropical freshwater fish belonging to the minnow family (Cyprinidae). It is native to the southeast of Asia where it lives in stagnant or flowing water; e.g. paddy fields or rivers. Zebrafish grow rapidly and have a short generation cycle of about 2-3 months (Bresch 1991. Scholz et al. 2008). Within favorable conditions female fish are able to spawn a large amount of eggs with a transparent chorion year round every 2-3 days. This characteristic makes them a very suitable test organism in environmental science as toxic effects on their larval development can easily be observed (Scholz et al. 2008). Apical observations performed on each tested embryo include: coagulation of embryos, lack of somite formation, non-detachment of the tail, and lack of heartbeat. These observations are used for the determination of lethality. Any positive outcome in one of these observations means that the zebrafish embryo is considered as dead. Additionally, hatching is recorded in treatment and control groups on a daily basis starting from 48 hours post fertilization. Observations are recorded every 24 hours until the end of the test.
The fish embryo toxicity test was conducted according to DIN EN ISO 15088 (2009), but the test duration was prolonged to 96 hours for all firefighting agents except X-fog. Each substance was examined in three
independent tests using five concentrations which were based on pre-test results and are shown in Table 4. Table 4. Concentrations (in vol%) prepared for the fish embryo toxicity test using Danio rerio
ARC Miljö 0.100 0.200 0.300 0.400 0.500
One Seven A 0.0003 0.0006 0.0013 0.0025 0.005
Sthamex 0.020 0.030 0.040 0.050 0.060
Towalex 0.060 0.070 0.080 0.090 1.00
X-fog 0.063 0.125 0.250 0.500 0.750
The eggs used in the tests originated from spawning groups (sex ratio 3:2 male/female) cultivated in the Institute for Environmental Research (RWTH Aachen University). The spawning groups were fed ad libitum on a daily basis using commercial flake food for fish (TetraMinTM Flockenfutter, Tetra GmbH, Melle, Germany) and living nauplius
18 larvae (Artemia spec.). Spawning was stimulated using artificial plants. As Danio rerio are spawn predators, the spawn was collected in glass trays covered with mesh to prevent predation. The trays were inserted into fish tanks shortly after power up of the illumination in the morning of a test day and retrieved after about 30 minutes.
Immediately after fertilization and before exposure the eggs were selected using a binocular microscope with at least 25-fold magnification. Only fertilized eggs between 8-cell stage and 128-cell stage were chosen. 10 eggs were used for each concentration. Each egg was exposed in a volume of 2 mL. For each test negative controls (40 eggs in artificial water) and positive controls (20 eggs in 3.75 mg/L 3,4-dichloroaniline) were entrained. The fish eggs were exposed in 24 well plates (TPP AG, Trasadingen, Swiss) and incubated at 26±1 °C. The evaluation of the test was carried out using an inverted microscope at magnifications of 40x and 100x. After an exposure time of 48 and 96 hours, lethal (coagulation of the embryo, non-detachment of the tail, non-detection of the heartbeat, lack of somite formation, the latter added according to OECD 236 (2013)) and sublethal (weak heartbeat, incomplete blood circulation, weak blood circulation, edemas on pericardium, edemas on tail, weak or absent pigmentation, lack of eye pigmentation, absence of eyes, underdevelopment, malformations, deformed or curved backbone, epiboly, absence or truncation of fins) endpoints were recorded. The statistical evaluation of 48- and 96 h-data was conducted using the software Prism (GraphPad Software, La Jolla, USA). The software combined the results from the three independent test replicates per substance to compute collective sigmoidal concentration-response curves and LC50 values using the method of least squares.
Results
In order to calculate a collective LC50 value the results of three independent fish embryo toxicity tests were used
to create a collective sigmoidal concentration-response curve (Figure 2). The highest concentration for all tests and firefighting agents resulted in complete mortality and the concentrations in between revealed a
concentration-response pattern.
The LC50(96h) were nearly identically compared to the LC50s found after 48 hours (Table 5). In all cases the
concentration-response curves determined after 48 hours and 96 hours were also very similar (Figure 2 and Appendix X). For each sample, at least the highest examined concentration (Table 4) resulted in complete mortality after 48 and 96 hours in all three tests conducted per sample. Notable large deviations between the tests were mainly found for Sthamex (concentrations 0.3 vol% and 0.4 vol% in Fig. 2).
19 Fig. 2. Concentration-response curve for A: ARC Miljö, B: One Seven A, C: Sthamex, D: Towalex, E: X-Fog determined in the in the fish embryo toxicity test (Danio rerio) after 48 hours as well as results of positive (□) and negative (Δ) controls. Each symbol represents the mean of three independent tests while error bars indicate the standard deviation. A 0.1 1 0 20 40 60 80 100 ARC Miljö positive control negative control Concentration [vol%] M o rt a lit y [ % ] B 0.00001 0.0001 0.001 0.01 0 20 40 60 80 100 One Seven positive control negative control Concentration [vol%] M o rt a lit y [ % ] C 0.01 0.1 0 20 40 60 80 100 Sthamex positive control negative control Concentration [vol%] M o rt a lit y [ % ] D 0.1 0 20 40 60 80 100 Towalex positive control negative control 0.04 Concentration [vol%] M o rt a lit y [ % ] E 0.1 1 0 20 40 60 80 100 X-Fog positive control negative control Concentration [vol%] M o rta lity [% ]
20 The lowest LC50(48h), indicating the highest toxic potential, was found for One Seven and the highest LC50(48h),
indicating the lowest toxic potential, was found for X-fog.
Table 5: LC50(48/96h)-values and 95 %-confidence limits (95 %-c.l.) determined for ARC Miljö, One Seven A, Sthamex, Towalex, and X-fog in the fish embryo toxicity test.
LC50(48h) 95 %-c.l. [vol%] LC50(96h) 95 %-c.l. [vol%]
[vol%] lower limit upper limit [vol%] lower limit upper limit
ARC Miljö 0.3386 0.3219 0.3560 0.3318 0.3178 0.3464
One Seven A 0.0010 0.0008 0.0012 0.0010 0.0008 0.0011
Sthamex 0.0365 0.0302 0.0440 0.0360 0.0299 0.0434
Towalex 0.0876 0.0845 0.0908 0.0864 0.0818 0.0912
X-fog 0.409 0.368 0.453 - - -
The negative control in each case resulted in a mortality lower than 10 % while the positive control (3.75 mg/L 3.4-dichloroaniline) always resulted in a mortality clearly higher than 10 %. Thus the validity criteria were fulfilled for all tests.
The additional lethal effect “lack of somite formation” (according to OECD 236 (2013)) was not observed in any case. Furthermore absence of pigmentation was the only sub-lethal effect found. This effect was just observed in one of the three tests in one concentration (0.5 vol%) on two embryos.
Overall the data revealed just slight deviations among the three tests and the results were well reproducible.
2.3.3 Acute immobilization test with Daphnia Magna
To determine acute effects towards primary consumers. X-Fog was tested in the acute immobilization test using the freshwater water flea Daphnia magna. This Crustacean from the genus Daphnia belongs to the order Cladocera and is a widely used model organism for assessing effects of chemicals and complex mixtures towards aquatic invertebrates. Daphnids are filter feeders and have an important position in aquatic food webs. As primary consumers they are a link between primary producers such as algae and higher-order consumers like fish.
In the acute toxicity test the immobilization of daphnids is used to quantify the hazard potential of substances in aqueous solutions. This acute test is one of the most commonly used bioassays for assessing the effects of chemicals. Some reasons for this are fast exposition-caused response, short generation cycles and easy rearing of daphnids under lab conditions.
The acute toxicity test was conducted according to OECD Guideline 202 (2004) using M4 medium. The test organism Daphnia magna STRAUS (clone 5) originated from the continuous-breeding of the Institute for Environmental Research (RWTH Aachen University).
X-Fog was examined in three independent tests using seven concentrations shown in table 6 with four replicates per concentration. A replicate contained five neonate (younger than 24 hours) Daphnia magna in a volume of 10 mL. Additionally four control replicates were entrained. The daphnids were incubated in darkness at 20±1 °C and
21 were not fed during the duration of the test. After 24 and 48 hours the numbers of immobile animals were determined by counting. The statistical evaluation was conducted using the software Prism (GraphPad Software. La Jolla. USA). The software combined the results from the three independent tests to compute one collective concentration-response curve (figure 3) and EC50 value using the model log(agonist) vs. normalized response
with variable slope.
Table 6. Concentrations (in vol%) prepared for the toxicity test using Daphnia magna
X-fog 0.017 0.031 0.063 0.125 0.250 0.500 1.000 ARC Miljö Test 1 0,01 0,05 0,1 0,5 1,0 Tests 2, 3 0,005 0,01 0,05 0,1 0,5 One Seven Test 1 0,0001 0,0005 0,001 0,005 0,01 Tests 2, 3 0,001 0,005 0,01 0,05 0,1 Sthamex Test 1 0,01 0,05 0,1 0,5 1,0 Test 2, 3 0,005 0,01 0,05 0,1 0,5 Towalex Test 1 0,01 0,05 0,1 0,5 1,0 Tests 2, 3 0,005 0,01 0,05 0,1 0,5 Results
In order to calculate a collective EC50(48h) value the results of three independent daphnia acute immobilization
tests were used to create a collective concentration-response curve (Fig. 3).
0.01 0.1 1 0 20 40 60 80 100 X-Fog Concentration [vol%] % Im m o b ili ty
Fig. 3. Concentration-response curve determined in the daphnia acute immobilization assay for X-Fog after 48 hours. . Each symbol represents the mean of three independent tests while error bars indicate the standard deviation. This does not apply to the lowest concentration (0.017 vol%). for this concentration the results of one test were discarded due to clearly non substance related immobilization of the daphnids.
22 At the lowest concentration (0.017 vol%) no immobilization was observed in two of the three tests. The high immobilization (65 %) found for this concentration in one of the tests was clearly non-substance related and therefore excluded from statistical analysis. The three highest concentrations (0.250 vol%. 0.500 vol% and 1.000 vol%) led to total immobilization in all cases. The concentrations in between revealed a concentration-response pattern. The EC50(48h) was 0.057 vol% (95% confidence interval: 0.051 to 0.062 vol%). There was no
immobilization observed in the negative control in each case. Oxygen concentrations and pH-values were monitored according to OECD Guideline 202. The pH-values did not change more than 1.5 units during incubation. Extraordinary low oxygen concentrations were found just for two single replicates in one of the three independent tests. These values seem to be outliners as for both concentrations the parallel replicate values were found to have normal oxygen concentrations.
Table 7. EC50(48h)-values and 95 %-confidence limits (95 %-c.l.) in the Daphnia magna toxicity test.
EC50(48h) 95 %-c.l. [vol%]
[vol%] lower limit upper limit
X-fog 0.057 0.051 0.062 ARC Miljö 0.1519 0.0645 0.3579 One Seven 0.0056 0.0040 0.0076 Sthamex 0.0960 0.0490 0.1879 Towalex 0.1686 0.0942 0.3016
2.3.4 Microtox
A standard method for toxicity testing is Microtox, which is an in vitro bioassay that uses a marine bacteria, Vibrio fisheri. The bacteria is natural luminesce, that is it sends out light as a part of its metabolism. When exposed to a toxic substance the function changes and a reduced output of light can be measured. Due to its simplicity the method has become a standard toxicity test for water, soil, and sediment.
The before mentioned firefighting agents together with additional agents were tested in this bioassay. The toxicity for Vibrio fischeri (stock 9) was measured according to standard method SS-EN ISO 11348-3:2008. Zink (II) was used as control was monitored together with pH, temperature and oxygen concentration and were all within control levels according to the method standard.
The test was evaluated statistically using regression analysis (curve fit) and the measured EC50 values can be seen
in table 8. The lowest toxicity for the marine bacteria Vibrio fischeri, e.g. the highest EC50 value was observed for
X-fog while the foam products showed approximately the same toxicity, up to 1000 times higher toxic response compared to X-fog.
23 Table 8. EC50(15min) in vol% for several firefighting agents in the Vibrio fischeri (Microtox) toxicity test. The
exposure time was prolonged to 30 min for X-fog due to low toxicity. Vol% X-fog (30 min) 21 One Seven A 0.030 Bioyellow 0.020 Forest 0.020 Towalex master 0.095
One Seven B-AR 0.049
ARC Miljö 0.016
Sthamex 0.085
X-foam 0.033
2.4 CONCLUSION
Class A and B foams on the Swedish market contains surfactants with the characteristic hydrophobic and hydrophilic properties. All class B foams included in the study contained fluorinated surfactants. The predicted long-term effect of the identified fluorinated surfactants is that they will undergo environmental transformation in more than one step until a carboxylic acid state with a fully fluorinated carbon chain is obtained (Moe et al. 2012; Wang et al. 2011), as illustrated below . From there no further transformation or degradation is
happening. These acids are as persistent in the environment as PFOS. They are however more water soluble than PFOS meaning that elimination time in organisms including humans are reduced, uptake in water rich crops like vegetables are increased, and removal from drinking water is more difficult.
Illustration 1. One of the predicted degradation products of 6:2 fluorotelomersulfonamide amine is PFHxA (Moe et al. 2012; Wang et al. 2011)
All products tested showed clear effects in all conducted bioassays. The strongest toxic effects were found for acute immobilisation test using the primary consumer Daphnia magna which are affected by firefighting agents at lowest concentration. The toxicity towards the green alga Desmodesmus subspicatus and embryos of Danio rerio was found to be lower. Differences in toxic responses between the tested agents were observed, X-fog showed the lowest toxic response based on concentrated product for all tests. The marine bacteria Vibrio fischeri actually started to grow by lower concentrations of X-fog and a high concentration of 21 vol% concentrated product was needed to obtain the effect concentration. This is probably due to the X-fog´s
composition of salts which functions as nutrition. There were minor differences between the foam products with exception for One Seven A that resulted in highest toxic response (e.g. lowest effect concentration). It should be noted that acute toxic effects are seen for class A foams as well as for class B foams and there are no differences in aquatic toxicity between these foam classes.
F F F F F F F F F F F OH O
24 Addition of foam and surfactants to water, both of which reduce the surface tension does not only lead to a higher toxic response but have also been shown to increase the solubility of the particular polyaromatics formed under fire in porous materials and may thereby contribute to increased pollution of the extinguishing water than if only water is used (Pablo et al 2011).
3. Formation of by-products during extinguishing using different
techniques
Materials like wood, plastic, fabrics, rubber, paper etc. generates hazardous substances when burning. The formation of hazardous by-products is not only determined by the material burning but also by the thermal conditions during extinguishing. Different firefighting agents and techniques help to extinguish fires in different ways. Some lower the temperature of the flue gas, while others lower the temperature of the burning material. The firefighting agent´s efficiency in lowering the temperature is crucial for reducing the formation of hazardous by-products. Depending on the composition of the firefighting agent, it is also possible that the agent itself can generate hazardous chemicals on contact with flames and hot surfaces. Another important parameter is how the extinguishing agent is introduced and distributed into the fire area.
A series of fire extinguishing tests were performed in order to study different firefighting agents and techniques influence on formation of hazardous by-products. The objective of the tests was to measure the formation of hazardous chemicals in gas and soot particles during fire extinguishing.
3.1 METHOD AND EXECUTION
Method and execution were focused on creating identical fire tests in where the only difference between tests should be the extinguishing technique. Fire extinguishing efficiency was not included in the evaluation. Two water-based systems and one foam system, commonly used for fires in buildings, were used:
Spray nozzle with water
Cutting extinguishing with water
Compressed air foam system (CAFS) with One Seven A Cutting extinguishing with water and additive X-fog
Fire tests were performed in containers that were equipped with identical interior consisting of double plasterboards, wooden studs, and identical furniture including sofa, carpet, mattress, pillows, table, lamp, electric cables, TV, computers and a plastic chair (figure 4). Most of the interior and furniture were newly purchased. Ignition was done in a standardized way, shown in figure 4, and quenching started about 10s after flashover. One and the same person, trained on all included techniques, extinguished all fires with the only instruction to put out the fires as if a normal firefighting incident. A heat camera was at the fire fighters disposal. Steal collectors were placed on the floor to retain firefighting water.
25 Figure 4. Picture of the container interior and the standardized ignition set-up (small picture)
Several samples and measurements were taken during the fire and extinguishing. Temperature was monitored by three different temperature probes situated at different positions in the container. Flue gas was sampled by low volume pumps (GSA SG4000. Messgerätebau GmbH. Gut Vellbrüggen. Germany) operated at air flows of 0.4-1 L/min connected to glass tubes, about 20 cm long, which were inserted through the wall of the container. One set of pump and tube was used to collect gases from the fire (until flashover) and another set was used to collect gases during the fire extinguishing phase until 5 minutes after the start of the extinguishing. Fire soot was sampled on stainless steel plates (length 500 mm. width 420 mm. thickness 1 mm); one mounted on the wall next to the gas sample glass tubes and one mounted in the opening of the container. Stainless steel plates were burned clean before usage and was not re-used. Flue gas samples and soot from the container opening was taken before and during extinguishing, respectively. The four tests of the different techniques were performed during three days at the facility Guttasjön, Södra Älvsborgs Räddnings Förbund (SERF). Container interiors including furniture were kept dry between mounting and fire test by a gas heater. Changes in conditions occurred however and it cannot be ruled out that outer circumstances influence the formation of by-products during extinguishing. In order to study bias from uncontrolled variables one test was performed twice with the aim to identify variables that differs due to weather circumstances rather than the extinguishing technique. The cutting extinguishing with water and additive X-fog was therefore repeated. Pictures from the five fire tests are shown in figure 5, together with notes on weather conditions.
1. Spray nozzle with water. Varying winds, partly away from the container opening
2.
Cutting extinguishing with water. Varying winds, partly towards container opening26 3. CAFS with One Seven A. Winds
directed towards container opening
4.Cutting extinguishing with water and additive X-fog. Winds directed towards container opening
5.
Cutting extinguishing with water and additive X-fog. Calm weather.Figure 5. Pictures from the start of each of the five fire tests together with weather notes for each test.
3.2 CHEMICAL ANALYSIS
It is relatively well known what by-products are formed during fire of different materials (Bengtsson and Antonsson 1993). A wide selection of parameters were chosen in this study to evaluate differences in formation of by-products depending on different extinguishing techniques.
Flue gas was sampled during the fires and during the extinguishing, separately, with respect to following parameters:
• Organic, non-polar substances (for example chlorinated and brominated dioxins and furans, polyaromatic hydrocarbons (PAHs))
• Isocyanates
• Volatile Organic Carbons (VOCs) • Inhalable dust and metals • Ammonia
• Aldehydes • Carbon monoxide
27 Fire soot was sampled on the pre-cleaned stainless steel plate mounted inside the container at the same height as the glass tube used for gas sampling, reflecting both fire and extinguishing, and at the container opening. The plate mounted at the opening was changed before extinguishing thus resulting in two soot samples, one during fire and one during extinguishing. After each test the soot were wiped off of the plates using Kleenex tissues. To minimize the risk of contamination each plate was used only once. The Kleenex tissues were analyzed with respect to:
Organic, non-polar substances (for example chlorinated and brominated dioxins and furans, polyaromatic hydrocarbons (PAHs))
Sampling and analysis of inhalable dust
Inhalable dust was collected using an IOM sampler (SKC Inc.. PA 15330 USA) with a 25 mm nitrocellulose membrane filter (Merk Millipore Ltd. Cork. Ireland. 3 m pore size) connected to a pump (GSA SG4000. Messgerätebau GmbH. Gut Vellbrüggen. Germany) operated at an air flow of 0.5 L/min. Determination of deposited amount of dust on the filters was made gravimetrically.
Analysis of element composition in inhalable dust
A standard analytical procedure of metal analysis on each filter was performed withinductively coupled plasma mass spectrometry (HP 4500 ICP-MS. Agilent Technologies Inc.) (NIOSH 1994a).
Aldehydes in flue gas
Aldehydes in flue gas were collected using an aldehyde sampler (Sep-Pak XPoSure Aldehyde Sampler. Waters Corp. Millford. MA. USA) consisting of silica impregnated with 2.4-dinitrophenyl-hydrazine (2.4-DNPH). The sampler was connected to a pump (GSA SG4000. Messgerätebau GmbH. Gut Vellbrüggen. Germany) operated at an air flow of 0.2 L/min. Aldehydes were analyzed by High Performance Liquid Chromatography (HPLC) with UV detection at 365 nm.
Ammonia in flue gas
Ammonia in flue gas was sampled using sorbent tubes filled with silica gel treated with sulfuric acid (SKC Inc. PA 15330 USA). The sorbent tubes were connected to a pump (GSA SG4000. Messgerätebau GmbH. Gut
Vellbrüggen. Germany) operated at an air flow of 0.2 L/min. Ammonia was extracted using Milli-Q water and then analyzed with ion chromatography according to NIOSH method 6016 (NIOSH 1994b).
VOCs in flue gas
VOCs in flue gas were sampled using Tenax TA adsorbent tubes (Markes International. Llanstrisant. Wales. UK) connected to a pump (GSA SG4000. Messgerätebau GmbH. Gut Vellbrüggen. Germany) operated at an air flow of 0.1 L/min. Prior to analysis an internal standard (3-methylpyridine) was added to the sorbent tubes. VOCs were desorbed and analyzed using a thermal desorber (Markes International) coupled to GC/MS (Agilent 7890B Agilent Technologies Inc.).
Organic and inorganic acids in flue gas
Organic and inorganic acids in flue gas were sampled using sorbent tubes filled with washed silica gel (SKC Inc. PA 15330 USA) connected to a pump (GSA SG4000. Messgerätebau GmbH. Gut Vellbrüggen. Germany) operated at an air flow of 0.1 L/min. Organic and inorganic acids were extracted using water as a solvent. Organic acids
28 were analyzed using ion chromatography according to NIOSH method 2011 (NIOSH 1994c). Inorganic acids were analyzed using ion chromatography according to NIOSH method 7903 (NIOSH 1994d).
Isocyanates in flue gas
Isocyantes in flue gas were collected using EZ4-NCO samplers (Supelco ASSETTM. Bellafonte. PA. USA) connected
to a pump (GSA SG4000. Messgerätebau GmbH. Gut Vellbrüggen. Germany) operated at an air flow of 0.2 L/min. Isocyantes were extracted and analyzed using LC/MS/MS according to Marand et al. (Marand et al. 2005). Chlorinated and brominated dioxins and furans (PCDD/Fs and PBDD/Fs)
ORBO 609 Amberlite XAD-2 (20/50) 400/200 mg (Sigma-Aldrich. Steinheim, Germany) was connected to pumps (GSA SG4000. Messgerätebau GmbH. Gut Vellbrüggen. Germany) operated at air flows of 0.4-1 L/min for flue gas sampling. Soot was collected by Kleenex wipes. The compounds were extracted during 24 hours with Soxhlet and toluene. The extract was split into two; one for dioxin analysis and one for PAHs. Clean-up was performed by using three different open columns (multilayer silica. AlOx and active carbon). To avoid photolytic degradation amber colored glassware or glassware covered with aluminum foil was used. PCDD/Fs and PBDD/Fs were analyzed on a Micromass Autospec Ultima operating at 10 000 resolution using EI ionization at 35 eV. All measurements were performed in the selective ion recording mode (SIR) monitoring the two most abundant ions of the molecular bromine or chlorine cluster. Quantification was performed using isotope dilution. For PCDD/Fs splitless injection was used to inject 1 μL of the extract on a 30 meter (0.25 mm i.d. 25 µm) DB-5MS column (J&W Scientific; Folsom. CA. USA). For PBDD/Fs a Programmed Temperature Vaporiser (PTV) injectior was used and 7 μL of the extract was injected on a 15 meter (0.25 mm i.d. 10 µm) DB-5MS column (J&W Scientific; Folsom. CA. USA).
PAHs
Sampling and extraction was identical with that of PCDD/Fs and PBDD/Fs and clean-up was performed using acidic silica. An Agilent 7890A gas chromatograph coupled to a 5975 low-resolution mass spectrometer using electron ionization (EI) at 70 eV was used for analysis. The separation capillary column was a Select PAH column, 30m x 0.25 mm, df = 0.15 µm provided by Agilent. Detection was made in single ion monitoring mode (SIM) and quantification was performed by isotope dilution.
3.3 RESULTS
The fire tests were performed by allowing the flue gases to ignite, making all flammable material being involved in the fire before starting the extinction. Sampling continued five minutes after start of extinguishing regardless when the fire was put out. Time to flashover varied from approximately 260s to 500s. Several steel containers on the container floor were used to collect remaining water after extinction. Table 9 shows descriptive data for the five fire tests.
29 Table 9. Descriptive data from the five fire tests.
Test Number of
re-ignitions Water consumption
Firefighting water collected
1. Spray nozzle with water 22 121 litres 2 litres
2. Cutting extinguishing with
water 4 62 liters 0.3 litres
3. Compressed air foam system (CAFS) with One Seven A
1 45 liters 0.2 litres
4. Cutting extinguishing with
water and additive X-fog 0 21 liters 0 litres
5. Cutting extinguishing with
water and additive X-fog 0 28 liters 0 litres
Time between first application and the fire was completely put down varied, and for test number 1 the sofa was still on fire after 5 minutes. The temperature decrease from the first application until five minutes passed can be seen in figure 6. Test 5 is not displayed for clarity reasons however the temperature curve was similar to test 4.
Figure 6. Temperature decrease in the container after the first application of firefighting agents (time 0 sec) until 5 minutes have passed. Filled symbols represents an application of firefighting agent. (Note: the starting temperature at 0sec could not be properly measured due to technical difficulties).
0 100 200 300 400 500 600 700 800 0 50 100 150 200 250 300 Tem p e ratu re (C)
Time after first application (sec)
1. Fog spear
2. Cutting extinguishing 3. CAFS OneSeven A 4. Cutting ext. X-fog
2
30 Inhalable dust and element composition
Low levels of inhalable dust were sampled in flue gas during fire extinguishing. Test 1 (spray nozzle) and test 2 (cutting extinguisher) generated particles that affected the sampling thus leading to underestimation of the inhalable dust fraction. Concentrations of 82, 185, and 320 mg/m3 were measured for test 1, 2 and 3,
respectively. In all three experiments the concentrations were over the Swedish occupational exposure limit (OEL) of 5 mg/m3. The inhalable dust fraction for test 4-5 was below the detection limit (Table A2). Metals
detected in the inhalable dust fraction can be seen in table A3. Magnesium (Mg), Manganese (Mn) and Antimony (Sb) were detected in test 1-3 but were less than LOD in test 4-5. Concentrations of Manganese and Antimony were above the Swedish OELs of 0.2 and 0.25 mg/m3 in all samples.
Aldehydes
Aldehydes measured and detected in flue gas are shown in table A4. Concentrations were generally low however the pattern reveals that other variables than the firefighting agent/technique influence the formation and measurement of aldehydes. Illustrated in figure 7 is the measured concentrations of acetaldehyde, two measurements (A and B) were performed for each test and a large variation between duplicates are seen. Moreover, test 4 and 5 uses the same firefighting agent/technique (cutting extinguisher with additive X-fog) and the concentration of acetaldehyde varies between 36 and 206 µg/L. Clearly, aldehydes are not suitable to use for evaluation of differences between firefighting agents.
Figure 7. Acetaldehyde in flue gas during fire extinguishing using 4 different firefighting agents/techniques (test 4 and 5 are test replicates, A and B are duplicate measurement for each test).
Ammonia
Ammonia could be detected in flue gas in three tests, all which used the cutting extinguisher (test 2, 4 and 5, see table A5). Concentration in test 3, for which only water was used, was 7.6 mg/m3 while test 4 and 5 measured 39
and 38 mg/m3, respectively. Ammonia is probably formed in test 4 and 5 as a result of the additive X-fog, that
contains salts like ammonium salts. 0 50 100 150 200 250 u g/ L Acetaldehyde
31 VOC
Table A6 shows individual and sum of VOCs in flue gas sampled during the 5 fire tests. There is a clear trend with highest concentrations for tests 1-3 compared to tests 4-5. Figure 8 illustrates concentrations of sum of VOCs and sum of VOCs including semivolatile organic carbons. Highest concentrations were measured for test 3, CAFS with One Seven A.
Organic and inorganic acids
Organic and inorganic acids in flue gas (mg/m3) could only be quantified in low concentrations as can be seen in
Table A7. No trend between the different firefighting agents could be seen.
Figure 8. Sum of VOC (µg/m3) in flue gas during extinguishing using 4 different firefighting agents/techniques
(test 4 and 5 are replicates). Isocyanates
A number of different isocyanates could be detected in flue gas as can be seen in table 10. Test 2 (cutting extinguisher with water) showed the highest concentration for several isocyanates. All isocyanates detected were above their OELs except for ethyl isocyanate. The OELs for isocyano acid, methyl isocyanate, phenyl isocyanate and toluene diisocyanate are 0,018, 0,024, 0,020 and 0,014 mg/ m3, respectively. An OEL for ethyl
isocyanate of 0,029 mg/ m3 can be derived from the OEL of methyl isocyanate.
Table 10. Isocyanates (mg/m3) in flue gas during fire extinguishing using 4 different firefighting
agents/techniques (test 4 and 5 are replicates).
µg/m3 Test 1 Test 2 Test 3 Test 4 Test 5
isocyano acid (ICA) 460 5700 610 140 350
methyl isocyanate (MIC) 650 930 470 210 270
ethyl isocyanate (EIC) 14 38 18 7 7
phenylisocyanate (FI) <LOD 53 60 <LOD 24
hexamethylene diisocyanate (HDI) <LOD <LOD <LOD <LOD <LOD
toluene diisocyanate (TDI) 45 2400 720 140 420
methylene diphenyl diisocyanate (MDI) <LOD 100 <LOD <LOD <LOD isophorone diisocyanate (IPDI) <LOD <LOD <LOD <LOD <LOD
22 472 22 700 21 752 15 078 16 356 37 086 44 454 58 646 23 584 23 202
TEST 1 TEST 2 TEST 3 TEST 4 TEST 5
u
g/
m3
32 Chlorinated and brominated dioxins and furans (PCDD/Fs and PBDD/Fs)
Dioxins and furans are formed during combustion if organic materials and chlorine or bromine are present. Chlorinated dioxins and furans (PCDD/Fs) could not be detected in flue gas samples in present study nor in soot taken from inside the container (table A8 and A9). A few congeners of chlorinated dioxins could be detected in low concentrations in soot from the plate in the opening of the container during fire extinguishing (table A10). Brominated dioxins were detected in both gas and soot samples. Flue gas samples contained several congeners of foremost furans however a pattern among the different tests is hard to see (table A11). Soot samples also contained mostly brominated furans, the soot swipe from inside the container contained less congeners and at lower concentrations compared to the other soot sample (table A12 and A13). Brominated furans in soot sampled during the extinguishing showed a clearer pattern and was also present in higher concentration. It is clear that the steel plate mounted in the opening of the container acted as a better condensation surface for brominated furans. The concentration of brominated furans in soot during extinguishing can be seen in figure 9. The pattern is that test 1 (spray nozzle) generated higher concentrations followed by test 3, CAFS with One Seven A.
Figure 9. Brominated furans (PBDFs) in fire soot (pg/m2) collected from the stainless steel plate mounted in the
container opening during fire extinguishing using 4 different firefighting agents/techniques (test 4 and 5 are test replicates)
PAHs
PAHs were detected in both flue gas and soot at relatively high concentrations. Figure 10 illustrates the PAH profile in flue gas sampled during fire extinguishing. A general trend is that lowest concentrations are found in test 4-5 with cutting extinguisher and X-fog. Soot samples contained a greater proportion of high molecular weight PAHs than the gas samples (figure 11). A smaller proportion of carcinogenic 4 to 6-ring PAHs was detected in soot samples from test 4-5 compared to test 1-3. PAHs in soot from test 2 (cutting extinguisher with water) could not be analyzed due to interferences. As for the brominated furans the steel plate mounted in the
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Test 1 Test 2 Test 3 Test 4 Test 5
